Re: Athlon PSE/AGP Bug

[Steve Brueggeman <brewgyman@mediaone.net>]

Actually, this one hit home this weekend.

I bought a new computer at a computer fair.
ECS K7S5A Motherboard
1.8Ghz (1.5actually) Athelon XP
3DForce2-MX
256MB DDR SDRAM PC-2100
AHA2940UW SCSI Controller
Compaq CDROM (reused from other upgraded system)

Spent all of Saturday trying to install Mandrake Linux 8.1 with random crashes,
segfaults, IDE-Timeouts.  Figuring this to be a memory problem, I ran memtest86
for 4 hours without any errors.  Was getting late, and said screw-it and went to
bed.  

Sunday, set the memory and CPU both to 100Mhz, still have problems. so I set
both back to 133Mhz.  Booted kernel 2.2.19 from 2nd CD in Mandrake set, and had
better luck.  Got it installed after 3 restarts.  Figuring this was somehow
related to APM or ACPI, I compiled a standard Marcello  kernel 2.4.17, but could
not make it through a whole compile without segfaults.  I'd just restart the
compile, letting make skip past the stuff that was already compiled.  Got an
average of 3-4 segfaults on compile run, and I tried about 5 runs.

Boot to linux-2.4.17 with APM and ACPI disabled, and only stuff in my system
enabled, and no Frame Buffer, still get segfaults when compiling kernel.

Then by sheer luck, while doing my normal check of linuxtoday.com, the top
article mentioned this Athelon bug.  I figure, "Hey, this sounds somewhat
familar", so I reboot with mem=nopentium as they suggested.

I've compiled the linux-2.4.17 about 10 times now, without a single segfault.

So, add me to the "Yes I've got this problem" list, and Yes, it appears to be
related to Nvidia AGP boards.

I've been running a 1Ghz Thunderbird for about a year now, with 2 different ATI
boards without any problems.  I'll try swapping the ATI and Nvidia display
adapters and see if it follows.

Steve Brueggeman

On Mon, 21 Jan 2002 10:17:10 -0800, you wrote:

>Andrea Arcangeli wrote:
>> 
>> ...
>> 
>> I think this is a very very minor issue, I doubt anybody ever triggered
>> it in real life with linux.
>
>It is said that the crashes cease when the `nopentium' option
>is used, so it does appear that something is up.
>
>I does seem that the nVidia driver is usually involved.
>
>> And Gentoo is shipping a kernel with preempt and rmaps included, so it
>> can crash anytime anyways, no matter how good the cpu is, so if they
>> got crashes with such a kernel (maybe even with nvidia driver) that's
>> normal. I was speaking today with a trusted party doing vm benchmarking
>> and rmap crashes the kernel reproducibly under a stright calloc while
>> swapping heavily, so clearly the implementation is still broken.
>
>-rmap is still young.  I did some heavy stress testing on it a couple
>of days ago and it was rock-solid, and performed well.
>
>> preempt additionally will mess up all the locking into the nvidia driver as
>> well. so if the combination of the two runs for some time without any
>> lockup that's pure luck IMHO.
>
>Yup.  But don't forget about the `nopentium' observations.
>
>-
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